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Re: [TowerTalk] [Bulk] Re: RF Ground is a Myth

To: "k1ttt@arrl.net" <k1ttt@arrl.net>
Subject: Re: [TowerTalk] [Bulk] Re: RF Ground is a Myth
From: Brian Carling <bcarling@cfl.rr.com>
Date: Tue, 20 Jan 2015 19:22:52 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I suspect it's not as conductive as some may have us think...

Best regards - Brian Carling
AF4K Crystals Co.
117 Sterling Pine St.
Sanford, FL 32773

Tel: +USA 321-262-5471




> On Jan 20, 2015, at 1:22 PM, David Robbins <k1ttt@verizon.net> wrote:
> 
> just remember when you do it to not use the point of an ohm meter probe.... 
> it is not easy to measure bulk material resistivity like in soil or concrete 
> or other types of materials.
> you need to have some relatively large surface area to contact the material, 
> which is hard to do with already poured concrete.
> 
> 
> Jan 20, 2015 12:59:36 PM, bcarling@cfl.rr.com wrote:
> 
> So far I am not convinced about using concrete. I'm going to do some 
> resistance testing on the concrete in my yard.
> 
> Best regards - Brian Carling
> AF4K Crystals Co.
> 117 Sterling Pine St.
> Sanford, FL 32773
> 
> Tel: +USA 321-262-5471
> 
> 
> 
> 
>> On Jan 20, 2015, at 10:13 AM, Grant Saviers wrote:
>> 
>> If your house slab was installed correctly with a vapor barrier and/or foam 
>> insulation, then it is insulated electrically from earth.
>> Tower bases make good Ufers as do perimeter foundations, so my towers and 
>> shop both had the rebar set as Ufers when constructed.
>> I also noticed that a new service transformer I had installed is set on a 
>> concrete vault that has a ground stub cast into the side. The power company 
>> used it, no ground rods. I'd estimate its surface area in contact with earth 
>> as more than 16 sq ft. Compare that to less than 2 sq feet for a 10' 3/4" 
>> ground rod.
>> 
>> Grant KZ1W
>> 
>> 
>>> On 1/19/2015 6:52 PM, Mike Reublin NF4L wrote:
>>> The electrician I had (who does a LOT of grounding work here) come out to 
>>> connect my tower ground to the service ground told me he would be glad to 
>>> drive the extra rods extending out from the tower, but doing so would add 
>>> no benefit at all. I have no idea if this is true or not. At some point, 
>>> lacking personal knowledge, ya have to take someone's word for it. My tower 
>>> megged out at 4 ohms.
>>> 
>>> Mike NF4L
>>> 
>>>> On Jan 19, 2015, at 8:29 PM, Brian Carling
> wrote:
>>>> 
>>>> The advice varies about this considerably. This week is the first time 
>>>> I've even heard of UF ER or conductive concrete!
>>>> 
>>>> The professional experts that I know recommend putting a 20 to 30 foot 
>>>> ground rod into the ground at each corner of your house and connecting 
>>>> heavy gauge copper conductors up to lightning rodsup on the roof.
>>>> 
>>>> It seems like if the only thing you need is a large area of this allegedly 
>>>> conductive concrete stuck in the ground, why not ground everything to the 
>>>> concrete slab your house sits on!!
>>>> 
>>>> Best regards - Brian Carling
>>>> AF4K Crystals Co.
>>>> 117 Sterling Pine St.
>>>> Sanford, FL 32773
>>>> 
>>>> Tel: +USA 321-262-5471
>> 
>> _______________________________________________
>> 
>> 
>> 
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